1. Field of the Invention
The present invention relates to a vibration controller and a vibration control method for active vibration insulators, vibration controller and method which can actively inhibit vibrations of vehicle engines from transmitting.
2. Description of the Related Art
Such vibration controllers for active vibration insulators have been known conventionally. For example, as disclosed in Japanese Unexamined Patent Publication (KOKAI) No. 11-259,147, a conventional vibration controller for active vibration insulators comprises a plurality of data maps, prepared in advance, on amplitude and phase data depending on vehicle driving conditions, selects an appropriate data map from the data maps, retrieves amplitude and phase data from the selected data map, and generates a signal for actuating an actuator for damping vibrations based on the retrieved amplitude and phase data.
Note herein that vehicle engine vibrations depend on the shift positions, for instance, being put in the “Driving” range or in the “Neutral” range. Moreover, vehicle engine vibrations depend on the states of air-conditioners being turned on or off as well. Accordingly, it is required to prepare a data map for each of vehicle driving conditions, such as the shift positions and the states of air-conditioners, for the conventional vibration controller disclosed in the aforementioned Japanese patent publication. Consequently, a lot of labor should be consumed to prepare such data maps.
Moreover, vehicle engine vibrations depend on the types of engines. Therefore, it is required to prepare a data map for each type of engines for the conventional vibration controller disclosed in the aforementioned Japanese patent publication. That is, the conventional vibration controller cannot cope properly with the fluctuations of controlled objects resulting from the differences between individual engines.
In addition, another vibration controllers have been known conventionally. One of such conventional vibration controllers retrieves a pulsating signal, which is for detecting a crankshaft position, from around an output shaft of engines, calculates an estimated value of torque variations from a change of the pulsating signal in a predetermined cycle by an adaptive control method, and generates a signal for actuating an actuator depending on a magnitude of the estimated value. However, the load for processing the computation is very high, because the conventional vibration controller calculates to find the torque vibrations. Accordingly, the conventional vibration controller needs an expensive control device, because it is required to exhibit high computing performance. Consequently, it is difficult to employ the conventional vibration controller for general vehicles, for example, for which it is necessary to remove the vibrations of engines simply and less expensively.